崔壮,侯冰. 深层页岩巴西劈裂破坏力学行为数值模拟研究[J]. 石油钻探技术,2024, 52(2):1-11. DOI: 10.11911/syztjs.2024032
引用本文: 崔壮,侯冰. 深层页岩巴西劈裂破坏力学行为数值模拟研究[J]. 石油钻探技术,2024, 52(2):1-11. DOI: 10.11911/syztjs.2024032
CUI Zhuang, HOU Bing. Numerical simulation of the damage behavior of Brazilian splits in deep shales[J]. Petroleum Drilling Techniques,2024, 52(2):1-11. DOI: 10.11911/syztjs.2024032
Citation: CUI Zhuang, HOU Bing. Numerical simulation of the damage behavior of Brazilian splits in deep shales[J]. Petroleum Drilling Techniques,2024, 52(2):1-11. DOI: 10.11911/syztjs.2024032

深层页岩巴西劈裂破坏力学行为数值模拟研究

Numerical simulation of the damage behavior of Brazilian splits in deep shales

  • 摘要: 为揭示页岩纹理特征与破坏强度之间的作用机理,利用黏聚力单元法建立了巴西劈裂三维数值模型,研究了纹理角度和纹理强度对页岩破坏模式和抗拉强度的影响,并利用声发射分布特征精确分析了裂纹演化过程。研究结果表明:巴西劈裂数值模拟结果与试验结果基本一致,利用黏聚力单元法可以准则预测岩石破坏行为;纹理角度和纹理强度耦合作用下页岩试样破坏模式分为6种;中心破坏的页岩试样,声发射能量-位移曲线以单峰值分布型为主,拉伸剪切复合破坏的页岩试样,声发射能量-位移曲线以多峰值分布型为主;页岩试样抗拉强度各向异性显著,相同纹理角度下,纹理强度越高,主裂纹越接近加载直径方向,试样抗拉强度越大。研究结果进一步揭示了深层页岩破坏机制,为页岩储层压裂设计提供了理论依据。

     

    Abstract: The fracture mode of deep shale determines the stability of engineering structures and the efficient development and use of energy. A three-dimensional numerical model of Brazilian splitting was used to investigate the relationship between shale texture characteristics and damage strength. The study analyzed the effects of texture angle and strength on shale damage pattern and tensile strength. The crack evolution process was accurately analyzed using acoustic emission distribution characteristics. The results indicate that the numerical simulation outcomes of Brazilian splitting agree with the experimental results. The cohesive element method can be used to predict the rock's damage behavior. The damage modes of shale specimens are classified into six categories under the coupling of the texture angle and the strength. For shale specimens with central damage, the acoustic emission energy-displacement curves are dominated by a single-peak distribution type. For specimens with mixed damage, including tension-shear mixed damage, the acoustic emission energy-displacement curves are dominated by a multiple-peak distribution type. The tensile strength of shale specimens is significantly anisotropic. The greater the texture strength and the closer the main crack is to the loading diameter direction, the higher the tensile strength of the specimens under the same texture angle. The results of the study also reveal the damage mechanism of shale and provide theoretical guidance for deep engineering applications.

     

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